Substrate based assays are typically relied upon to detect the presence of bacterial and other pathogens. Such standard microbiological methods for detecting microorganisms do not require expensive equipment or lab facilities, are generally easy to carry out, and provide high levels of selectivity and sensitivity. However, such methods are slow, as they require a pure culture of the target organism, which can take a day or more to cultivate or grow.
Certain molecular biology techniques are alternatives to the standard microbiological tests. For example, serological methods have gained wide acceptance. Such techniques do not require cultivation of the biological sample, thus reducing the time necessary to perform the test. Other techniques can utilize phage, or bacteriophage in the case of bacteria, to infect the target organism. The infected bacterium can subsequently emit light or release certain nucleotides or release progeny phage. However, these tests cannot capitalize on the ability to detect progeny phage. Further, the tests are time consuming to perform and do not achieve the same levels of selectivity and sensitivity. They are also more expensive and require a more highly trained lab technician than do the substrate based assays.
Some optical based detection methods utilize optical tags, such that the tagged organism is illuminated or visualized with a spectrometer. The optical-based detection methods can rely on beads or other particles that produce a signal. However, these tests do not attempt to detect progeny phage.
Thus, a method for detecting progeny phage that utilizes an optical-based detection method combined with the sensitivity, selectivity and lower cost of the substrate based assay and the quick results of a molecular biology technique is needed. This and other needs are addressed by the present invention.